// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Collections.Concurrent;
using JetBrains.Annotations;

namespace Microsoft.EntityFrameworkCore.Update.Internal;

/// <summary>
///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
///     the same compatibility standards as public APIs. It may be changed or removed without notice in
///     any release. You should only use it directly in your code with extreme caution and knowing that
///     doing so can result in application failures when updating to a new Entity Framework Core release.
/// </summary>
public class KeyValueIndexFactorySource : IKeyValueIndexFactorySource
{
    private readonly ConcurrentDictionary<IKey, IKeyValueIndexFactory> _factories = new();

    /// <summary>
    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    public virtual IKeyValueIndexFactory GetKeyValueIndexFactory(IKey key)
        => _factories.GetOrAdd(key, Create);

    /// <summary>
    ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///     any release. You should only use it directly in your code with extreme caution and knowing that
    ///     doing so can result in application failures when updating to a new Entity Framework Core release.
    /// </summary>
    public virtual IKeyValueIndexFactory Create(IKey key)
        => (IKeyValueIndexFactory)typeof(KeyValueIndexFactorySource).GetTypeInfo()
            .GetDeclaredMethod(nameof(CreateFactory))!
            .MakeGenericMethod(key.GetKeyType())
            .Invoke(null, new object[] { key })!;

    [UsedImplicitly]
    private static IKeyValueIndexFactory CreateFactory<TKey>(IKey key)
        where TKey : notnull
        => new KeyValueIndexFactory<TKey>(key.GetPrincipalKeyValueFactory<TKey>());
}
